Strap yourselves in, folks! It's Joss Whedon and John Cassaday's final arc on Astonishing X-Men. After the shocking events of the previous three stories, the X-Men are off to protect the Earth from its destruction at the hands of Breakworld. When it's all over, nothing will ever be the same. Whedon and Cassaday prove they are more than Astonishing. They are Unstoppable!